1. The Field of the Invention
The present invention is generally related to optical transceivers used in fiber optic communications systems. In particular, exemplary embodiments of the invention relate to methods for assembling an optical transceiver.
2. Related Technology
Fiber optic technology is increasingly employed as a method by which information can be reliably transmitted via a communications network. Networks employing fiber optic technology are known as optical communications networks, and are marked by high bandwidth and reliable, high-speed data transmission.
Optical communications networks employ optical transceivers in transmitting information via the network from a transmission node to a reception node. An optical transceiver at the transmission node receives an electrical signal from a network device, such as a computer, and converts the electrical signal via a laser to an optical signal. The optical signal can then be emitted by the transceiver and transmitted in a fiber optic cable via the optical network, such as a LAN backbone, for instance. The optical signal is then received by a reception node of the network. Once received by the reception node, the optical signal is fed to another optical transceiver for conversion via a photodetector into electrical signals. The electrical signals are then forwarded to a host device, such as a computer, for processing. The optical transceivers described above have both signal transmission and reception capabilities; thus, the transmitter portion of the transceiver converts an incoming electrical signal into an optical signal, whereas the receiver portion of the transceiver converts an incoming optical signal into an electrical signal.
In addition to the laser and photodetector mentioned above, several other components are also internally included within a typical transceiver module. Among these are a controller, which governs general operation of the transceiver, a laser driver for controlling operation of the laser in the transmitter portion, and a post-amplifier for controlling the photodetector that converts incoming optical signals into electrical signals in the receiver portion.
The above components are typically disposed as chips and/or integrated circuits on multiple substrates or PCB boards within the transceiver. For example, in a typical transceiver, the controller, laser driver, and post-amplifier are located on a main PCB, while the laser and photodetector reside on separate substrates disposed in a transmitter optical subassembly (“TOSA”) and receiver optical subassembly (“ROSA”), respectively.
Though the typical transceiver design discussed above has been successfully implemented in a large number of manufactured transceivers, it nonetheless introduces a number of challenges. First, the use of multiple substrates for the placement of transceiver components complicates both the internal design and manufacture of the device. In some applications, where simple transceiver design is desired, this complexity is disadvantageous.
Second, the placement of the laser and photodetector on separate substrates not only involves extra componentry and additional assembly steps, but it also complicates the process of aligning the laser and photodetector. During transceiver assembly, the laser must be properly aligned to effectively transmit the optical signals it produces during transceiver operation through a fiber optic cable that connects to the transceiver. Similarly, the photodetector must be properly aligned within the transceiver to effectively receive optical signals received from another fiber optic cable attached to the transceiver. If the laser or photodetector is misaligned, effective optical communication by the transceiver can be severely hampered. In typical transceivers, alignment of the laser and photodetector must take place separately, wherein one component, then the other, is aligned. This need for separate alignment undesirably equates to prolonged transceiver assembly and calibration times.
In light of the above discussion, a need currently exists for a transceiver that benefits from simple design and streamlined assembly. In particular, a transceiver is needed that consolidates optical component alignment in order to simplify transceiver alignment and calibration. Moreover, such a transceiver should include a minimum of parts and should enable the assembly thereof without the use of numerous fastening devices.